Magnetic sealants of the prior art are typically mixtures of synthetic polymers, resins, plasticizers and magnetically chargeable particles. Typically, these sealants are prepared in tape form, through an extrusion process and used to seal seams in sheet metal structures. The magnetic tape is placed over the seam and remains in position during processing through the magnetic attraction between the sealant and the substrate until the structure is passed through a heating process which causes the tape to melt and flow into the seam sealing any gaps or openings that may have existed.
However, these materials are not useful in situations where a sizable gap exists, for example, due to the overlapping of two surfaces, especially where the gap is irregular in that the opening varies in dimension.
Therefore, what is needed in this art is a magnetic sealant or adhesive which will remain in place during processing but when exposed to heat will be capable of expanding and filling such gaps more completely.